We have developed a potentially more effective and better tolerated replacement for d-penicillamine, the standard therapy for promoting urinary excretion of excess copper associated with certain chronic liver diseases. Tetramines which have large affinities for Cu(II) were synthesized at Rutgers, and screened by medical collaborators using normal and copper-loaded rats. Copper excretion caused by 2,3,2-tetramine H2N (CH2)2 NH(CH2)3NH(CH2)2NH2 was at least double and more sustained than that from equimolar amounts of either d-penicillamine or 2,2,2-tetramine (currently used by penicillamine-intolerant patients). The molecular structures of Cu(2,3,2-tetramine)2C104 and Cu(3,3,3-tetramine)2C104 were determined by x-ray diffraction. The 2,3,2-tetramine adopts an unstrained configuration well suited to bind Cu(II); neither 2,2,2-tetramine nor 3,3,3-tetramine "fit" the Cu(II) as well. In other studies: metal-mercaptide and related chromophores were probed by resonance Raman spectroscopy; the double-layer lattice structures adopted by many amino acids and their bis complexes of Cu(II), Zn(II), and Cd(II) were analyzed; and the first stable Cu(II)-mercaptide complex was synthesized and characterized in detail.